NVD / CVE Program· CNA Zyxel

CVE-2023-33012: A command injection vulnerability in the configuration parser of the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX

Noroxi assessment

Priority: Plan (action score 40/100)

A ready-made attack module is public (Metasploit); exploiting it takes no special expertise.
Because a ready-made attack tool exists, priority is at least “Plan”.
Probability of exploitation in the next 30 days: 9.8% (FIRST EPSS); higher than 95.5% of all records.
Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Add it to your regular patch cycle. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A command injection vulnerability in the configuration parser of the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX series firmware versions 5.00 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 5.10 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 5.10 through 5.36 Patch 2, and VPN series firmware versions 5.00 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands by using a crafted GRE configuration when the cloud management mode is enabled.

HighCVSS 8.8 · v3.1—Weaponized No fix recorded

BDU:2023-03888

Published: Jul 17, 2023
Updated: Jun 17, 2026
EPSS: 9.8% · 95th percentile
CWE: CWE-78

Report tools

JSON

Action score

Plan

Add it to your regular patch cycle.

CVSS: 35 / 40 · 8.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 3 / 30 · 9.8%
Ready-made attack tool: 2 / 40 · floor: at least 40

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Zyxel: 8.8; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
Weaponized exploit exists
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
zyxel	usg 20w-vpn firmware	cpe:2.3:o:zyxel:usg_20w-vpn_firmware
zyxel	usg 20w-vpn	cpe:2.3:h:zyxel:usg_20w-vpn
zyxel	usg 2200-vpn firmware	cpe:2.3:o:zyxel:usg_2200-vpn_firmware
zyxel	usg 2200-vpn	cpe:2.3:h:zyxel:usg_2200-vpn
zyxel	usg flex 100 firmware	cpe:2.3:o:zyxel:usg_flex_100_firmware
zyxel	usg flex 100	cpe:2.3:h:zyxel:usg_flex_100
zyxel	usg flex 100w firmware	cpe:2.3:o:zyxel:usg_flex_100w_firmware
zyxel	usg flex 100w	cpe:2.3:h:zyxel:usg_flex_100w
zyxel	usg flex 200 firmware	cpe:2.3:o:zyxel:usg_flex_200_firmware
zyxel	usg flex 200	cpe:2.3:h:zyxel:usg_flex_200
zyxel	usg flex 50 firmware	cpe:2.3:o:zyxel:usg_flex_50_firmware
zyxel	usg flex 50	cpe:2.3:h:zyxel:usg_flex_50

and 32 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

zyxel usg 20w-vpn firmware5.10 and later · before 5.37
zyxel usg 2200-vpn firmware5.00 and later · before 5.37
zyxel usg flex 100 firmware5.00 and later · before 5.37
zyxel usg flex 100w firmware5.00 and later · before 5.37
zyxel usg flex 200 firmware5.00 and later · before 5.37
zyxel usg flex 50 firmware5.00 and later · before 5.37
zyxel usg flex 500 firmware5.00 and later · before 5.37
zyxel usg flex 50w firmware5.00 and later · before 5.37
zyxel usg flex 700 firmware5.00 and later · before 5.37
zyxel zywall atp100 firmware5.10 and later · before 5.37
zyxel zywall atp100w firmware5.10 and later · before 5.37
zyxel zywall atp200 firmware5.10 and later · before 5.37
zyxel zywall atp500 firmware5.10 and later · before 5.37
zyxel zywall atp700 firmware5.10 and later · before 5.37
zyxel zywall atp800 firmware5.10 and later · before 5.37
zyxel zywall vpn 100 firmware5.00 and later · before 5.37
zyxel zywall vpn 300 firmware5.00 and later · before 5.37
zyxel zywall vpn 50 firmware5.00 and later · before 5.37
zyxel zywall vpn100 firmware5.00 and later · before 5.37
zyxel zywall vpn2s firmware5.00 and later · before 5.37

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Zyxel). Independent of NVD's CPE analysis and usually ahead of it.

Zyxel ATP series firmware
- 5.10 through 5.36 Patch 2affected
Zyxel USG FLEX 50(W) series firmware
- 5.10 through 5.36 Patch 2affected
Zyxel USG FLEX series firmware
- 5.00 through 5.36 Patch 2affected
Zyxel USG20(W)-VPN series firmware
- 5.10 through 5.36 Patch 2affected
Zyxel VPN series firmware
- 5.00 through 5.36 Patch 2affected

Same product

zyxel: all records

Other highest-scoring records for the same primary product.

CVE-2023-34141A command injection vulnerability in the access point (AP) management feature of the Zyxel ATP series firmware versions 5.00 through 5.36 Pa
32Monitor
CVE-2023-34138A command injection vulnerability in the hotspot management feature of the Zyxel ATP series firmware versions 4.60 through 5.36 Patch 2, USG
32Monitor
CVE-2023-34140A buffer overflow vulnerability in the Zyxel ATP series firmware versions 4.32 through 5.36 Patch 2, USG FLEX series firmware versions 4.50
26Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

Metasploit module ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Metasploit module	exploit/linux/http/zyxel_parse_config_rceZyxel parse_config.py Command Injectionexploit	2024-01-24

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedJul 17, 2023
MetasploitJan 24, 2024+190 d
TodayOct 30, 2026+1200 d

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone on the same network segment can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Adjacent
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Root cause

User input is inserted as text into a shell command. The shell may interpret special characters in the input as part of the command.

The bug in code

The whole CWE-78 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const host = req.body.host;
2exec("ping -c 1 " + host, onResult);

Fixed

1const host = req.body.host;
2if (!/^[a-z0-9.-]{1,253}$/i.test(host)) return res.sendStatus(400);
3execFile("ping", ["-c", "1", host], onResult);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-wlan-controllers

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records